Multi-tank water heater



Aug. 9, 1966 J, H. MCCARTHY, JR 3,255,041

MULTI-TANK WATER HEATER Filed May 18, 1964 3 Sheets-Sheet 1 m wwwfm I United States Patent 3,265,041 MULTI-TANK WATER HEATER Joseph H. McCarthy, .lr., La Grange, Ill., assignor to Rheem Manufacturing Company, Chicago, 111., a corporation of California Filed May 18, 1164, Ser. No. 368,013 Claims. (Cl. 122-17) This invention relates to improved water heaters and it particularly relates to high capacity and high input water heaters which are of relatively economical construction.

In tank type water heaters, the tank is used to store Water While the outside surfaces of the tank are used for heat transfer purposes. In higher input water heaters, it is common practice to provide one or more internal flue ways in the center of the storage tank so as to provide an additional heat transfer surface or the entire heat transfer surface. Such higher capacity Water heaters have significant disadvantages. One such disadvantage is that, particularly in the large commercial type units, heavy gauge steel is required in constructing the tank in order to compensate for high stresses encountered in the large cylindrical tanks. Furthermore, the provision of additional tubular flue ways Within the water tank add additional weight to the already heavy tanks.

The large water heater tanks also present considerable problems with regard to transportation and maintenance, because of their excessive size. For example, it is often necessary to first install a large water heater tank in a new building, then construct walls around the installed tank; also, if it is necessary to replace the tank for any reason, the removal of the old tank and the installation of a new one presents a great problem since a Wall may have to be partially dismantled in order to remove the old tank and to install the new tank.

Furthermore, when flues are added to glass lined tanks, it is diflicult to construct the multi-flue tank without destroying the glass lining in the area of the lower and upper heads Where the flue ways are located.

It is therefore an important object of this invention to provide an improved water heater wherein the disadvantages of prior water heater constructions are substantially avoided.

It is also an object of this invention to provide an improved water heater having a plurality of Water storage tanks, whereby there is an increased heat transfer surface area yet a decreased quantity of steel required than for a single tank having the same volume capacity as the plurality of tanks.

It is another object of this invention to provide a water heater having a plurality of water storage tanks whereby less floor space is required than for a large multi-flue tank having an equivalent capacity and having substantially the same height.

It is a further object of this invention to provide a multi-tank water heater whereby, in case of tank failure, only the tank that fails needs to be replaced.

It is yet another object of this invention to provide an improved water heater of multi-tank construction wherein the improved construction requires less height than a single tank unit having an equal capacity per unit height.

It is still a further object of this invention to provide an improved water heater which is characterized by its economy of construction.

It is still another object of this invention to provide an improved water heater wherein multiple tanks are provided rather than a single tank of equivalent capacity, whereby transportation and installation thereof are greatly facilitated.

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Further purposes and objects of this invention will appear as the specification proceeds.

Particular embodiments of the present invention are illustrated in the accompanying drawings wherein:

FIGURE 1 is a front elevational, partially sectioned View of my improved water heater construction;

FIGURE 2 is a side elevational, partially sectioned View of the embodiment of FIGURE 1;

FIGURE 3 is a sectional view taken along the line 33 of FIGURE 2; and

FIGURE 4 is a view, similar to FIGURE 3, showing alternate means for interconnecting the tanks of my multitank water heater.

Referring to the drawings, my improved water heater construction 10 includes a plurality of water storage tanks 12 which have their outer peripheries maintained in close proximity. Although my water heater construction 10 may have any desired number of storage tanks 12, the present description will relate to a water heater 10 having four storage tanks 12. Preferably, the tanks 12 are substantially cylindrical in shape and are positioned in an upright or substantially vertical position. The tanks 12 are enclosed at their upper and lower ends by upper heads 14 and lower heads 16, respectively. The water tanks 12 are ordinarily made of steel and may be constructed in a conventional manner, as by welding.

As shown in FIGURES 3 and 4, in order to realize all of the advantages of the present invention, when four or more tanks 12 are utilized, imaginary lines joining the centers of adjacent tanks are maintained at substantially right angles to each other While the outer peripheries of the tanks are in close proximity or in substantial contact so as to provide a substantial line contact 18 therebetween. The adjacent tanks 12 form a plurality of flue ways 29 between their outer peripheries for providing heat transfer to the water in the tanks. A plurality of baflles 21 are passed downwardly through the flue ways 20 to assist in the heat transfer from the hot gases to the walls of the tanks 12.

The water storage tanks 12 are maintained in close proximity or incontact and in alignment with each other by a pair of mating wraparound support members or panels 22. The supports 22 may be curved to substantially conform to the outer peripheries of the tanks 12 at their outer corners. The support members 22 provide support for the tanks 12, maintain them in the desired relationship to each other, and maintain them in an upright position. Suitable means may be provided for securing the flanges 24 of each of the panels 22 together. The upper ends of the co-operating wraparound members 22 are covered by a top panel 26 which is secured to the support panels 22 by any suitable means. The top panel 26 is spaced from the upper heads 14 of the tanks 12 whereby a flue gas collector space 28 is provided between the panel 26 and the upper heads 14. The wraparound members 22 and the top panel 25 are covered by a suitable thickness of insulating material 30, which may be any of the commercially available types of insulation commonly used for water heater constructions.

.An outer enclosure, generally 32 is provided for enclosing the multiple tanks 12 and the insulation 30. The enclosure 32 includes a pair of removable side panels 34 which are secured to a rear panel 36. A pair of forward panels 33 extend forwardly from and are secured to the side panels 34 and are in turn secured to the front panel 40. A removable door 42, having a handle 44, is located in the lower portion of the front panel 40; the door 42 provides access to the control area 46 which is located between the door 42 and the intermediate insulation support panel 48, which is positioned in front of and adjacent the insulation 30 which extends along the forward portion of the water storage tanks 12.

Although various heating means may be used, in the embodiment shown, gas burners are used.

Positioned within the control space 46 and mounted on the intermediate panel 48 is a gas burner control 50. Tubing 52 extends from the gas control 50 and is connected to the individual burners 54, to thereby introduce gas thereto. The burners 54 are supported by brackets 56 which are mounted on a bottom panel 58; the bottom panel 58 is secured to the side panels 34, rear panel 36 and front panel 40. The bottom panel 40 in turn is supported on a base 60 which supports the entire water heater construction 10.

At the lower portion of the door 42 there is an air inlet panel 64 having a plurality of openings therein; a bafile late 66 is angularly mounted on the front panel 40 near the lower end of the panel 64 and is positioned opposite the openings in the panel 64, whereby air passes through the panel 64, is directed against and around the panel 66, then through the opening 68 in one of the wraparound members 22, and to the burners 54. The opening 68 not only provides an opening for the passage of air, but it also provides access to the burners 54 located in the burner space 72.

For the removal of flue gases, a vent or opening 74 extends from the flue gas collector space 28 outwardly to a vent hood 76. In order to facilitate the removal of flue gas, a plurality of openings are provided in an air inlet panel 78 whereby air passing through the openings is baffled upwardly by a baflie plate 80 which is angularly mounted between the front panel 40 and the intermediate panel 48. This air draws the flue gases from the collector space and then upwardly through the opening 82 in the top panel 84 of the enclosure 32; alternatively the hood 76 may have a vent opening 83 in one of the side walls thereof.

Referring to FIGURES 1-3, a cold water inlet 86 passes through one of the side panels 34, the insulation 30, one of the wraparound members 22 and into one of the water storage tanks 12. Tubing 88 is adapted to interconnect and direct cold water to the remaining tanks 12; in the embodiment shown the tanks 12 are in parallel connection. The tubing 88 is enclosed by the insulation 30 and tubes extend from the tubing 88 to the individual tanks 12.

Cold water is directed into the lower portions of the heater tanks 12, so that the incoming cold water is in close proximity to the burners.

In a similar manner, a hot water outlet 90 extends outwardly from one of the tanks 12 and is adapted to interconnect the remaining tanks in parallel by means of tubing 92 and tubes 94, whereby the heated Water passes outwardly from the water heater 10. The hot water outlet means for each of the tanks 12 is at the upper portions thereof. Preferably, outlet conduit 99 extends from a tank other than the tank to which the cold water inlet 86 is connected, in order to assure substantially even heating throughout the four tanks.

Referring to FIGURE 4, alternatively, the hot water outlet 90 and the cold water inlet 36 may be connected to one of the tanks 12, while the remaining tanks 12 are interconnected by suitable conduit means or close nipples 96; four interconnecting nipples 96 are positioned at the lower portions of the tanks 12 for the cold water, while four interconnecting nipples 96 are provided at the upper portions of the tanks 12 for the hot water. The nipples 96 are located along the lines of contact 18 between the abutting water heater tanks 12, whereby water circulates freely through the four tanks 12.

Although as heat is applied to the water in the tanks 12 by the burner means 54, the flue ways 20 between the outer peripheries of the tanks 12 make it unnecessary to provide internal fiues within the tanks 12, if desired, internal flues 98 may be provided, as shown in FIGURE 4. In the case of glass lined tanks, it is advantageous to uti- 4 lize my multi-heater 10 with only one internal flue 98 in order to avoid the problem of destroying the glass lining as encountered in the construction of multi-flue tanks.

As previously set forth, one of the important advantages of my multi-tank water heater construction 10 is that it provides greater heat transfer surface area while the weight of steel used is less than for a single tank of similar construction having the same volume capacity as the multiple tanks. Thus, in comparing a single tank of diameter D with four tanks of diameter D/2, the total cross-sectional area of four smaller tanks is equal to the crosssectional area of a single larger tank. The four tanks also have the same volume per unit height as a single larger tank. Since the stress encountered in a pressure cylinder due to internal pressure is directly proportional to its diameters, there is one half of the stress in four tanks of diameter D/ 2 than in one tank of diameter D. Although the cylindrical shells of the tanks are of the same total weight, the total weight of the steel in the heads and bottoms for four tanks of diameter D/2 is one half the weight of steel required for the heads and bottoms of a single tank of diameter D.

With respect to heating area, by using four tanks of diameter D/2, there is twice as much heating area on the cylindrical shells than on the shells of a single tank of diameter D. The result is a significantly increased heat transfer area with the multi-tank construction. Thus, surprisingly the multi-tank water heater 10 has an increased heat transfer surface area and yet a reduced quantity of steel when compared to a single tank having the same cross-sectional area and volume capacity as the multi-tank construction.

Also, if a tank fails in the multi-tank water heater construction, only the tank that fails needs to be replaced; in a single tank construction, the single more costly tank must be replaced and dismantled. Furthermore, in the multi-tank construction, the individual tanks can be shipped before assembly and can then be assembled at the destination. Thus, transportation and installation problems are greatly alleviated by the multi-tank construction.

While in the foregoing, there has been provided a detailed description of particular embodiments of the present invention, it is to be understood that all equivalents obvious to those having skill in the art are to be included within the scope of the invention as claimed.

What I claim and desire to secure by Letters Patent is:

1. A water heater comprising a plurality of upright, substantially cylindrical water storage tanks, said tanks being mounted with their outer peripheries being in substantial contact so as to provide substantial line contact therebetween, flue means defined between said tanks, cold water inlet means connected in parallel to the lower portions of said tanks, hot water outlet means connected in parallel to the upper portions of said tanks, means positioned below said tanks for heating the water in said tanks, and insulating means substantially surrounding said tanks and said heating means.

2. A water heater comprising a plurality of substantially cylindrical upright water storage tanks, said tanks being mounted with their outer peripheries in substantial contact so as to provide substantial line contact therebetween, flue means defined between the outer peripheries of said tanks, cold water inlet means and hot water outlet means connected in parallel to said tanks, means below said tanks for heating the Water in said tanks, a flue gas collector space positioned above said tanks, insulating means substantially surrounding said tanks, said heating means and said collector space, and flue gas vent means passing from said flue gas collector space.

3. A water heater comprising a plurality of upright, substantially cylindrical water storage tanks, said tanks having imaginary lines joining the centers of adjacent tanks in substantial right angle alignment with each other, the outer peripheries of said tanks being in substantial contact so as to provide substantial line contact therebetween,

flue spaces defined between the outer peripheries of said storage tanks, cold water inlet means connected to the lower portions of the tanks, hot water outlet means connected to the upper portions of said tanks, gas burner means positioned below said tanks for heating the water stored in said tanks, a flue gas collecting space positioned above said tanks, insulating means substantially surrounding said tanks, said heating means, and said flue gas collecting space, and flue gas vent means connected to said flue gas collecting space.

4. The water heater of claim 3 wherein means surround said tanks for maintaining said tanks in substantial line contact and in alignment with each other.

5. The water heater of claim 3 wherein four cylindrical water storage tanks are provided and bafiles are provided in said flue spaces defined between said water storage tanks.

- References Cited by the Examiner UNITED STATES PATENTS 15 FREDERICK L. MATTESON, 111., Primary Examiner.

ROBERT A. DUA, Examiner. 

1. A WATER HEATER COMPRISING A PLURALITY OF UPRIGHT, SUBSTANTIALLY CYLINDRICAL WATER STORAGE TANKS, SAID TANKS BEING MOUNTED WITH THEIR OUTER PERIPHERIES BEING IN SUBSTANTIAL CONTACT SO AS TO PROVIDE SUBSTANTIAL LINE CONTACT THEREBETWEEN, FLUE MEANS DEFINED BETWEEN SAID TANKS, COLD WATER INLET MEANS CONNECTED IN PARALLEL TO THE LOWER PORTIONS OF SAID TANKS, HOT WATER OUTLET MEANS CONNECTED IN PARALLEL TO THE UPPER PORTIONS OF SAID TANKS, MEANS POSITIONED BELOW SAID TANKS FOR HEATING THE WATER IN SAID TANKS, AND INSULATING MEANS SUBSTANTIALLY SURROUNDING SAID TANKS, AND SAID HEATING MEANS. 